IS 9698 : 1995 ( Reaffirmed 2001 ) Indian Standard LINING OF CANALS WITH POLYETHYLENE FILM CODE OF PRACTICE (First Revision) UDC 626.823.916 : 006.76 0 BIS 1995 BUREAU MANAK OF INDIAN 9 BAHADUR STANDARDS SHAH ZAFAR MAYfiG BHAVAN, NEW DELHI 110002 October 1995 Price Group 3 Irrigation Canals and Canal Linings Sectional Committee, RVD 13 FOREWORD This Indian Standard ( First Revision ) was adopted by the Bureau of Indian Standards, after the draft finalized by the Irrigation Canals and Canal Linings Sectional Committee, had been approved by the River Valley Division Council. Lining of canals is considered an important feature of irrigation projects as it not only minimizes the loss of water due to seepage but also results in achieving considerable economy in the use of cultivable land which would otherwise be prone to water logging due to rise in water table. Further, the water thus saved, can be usefully employed for the extension and improvement of irrigation facilities. Lining of water courses in the areas irrigated by tube-wells assumes special significance as the pumped water supplied is relatively more costly. Further, lining of canals permits the adoption of high velocities resulting in proportionate savings of the crosssectional areas of the channel and land width required, with corresponding saving in the cost of excavation and masonry works, which may in certain cases offset completely the extra cost of lining. Also, thelining ensures stability of channel sections thereby reducing the maintenance cost. The benefits that accrue from lining~of canals justify the initial capital cost and, therefore, there is now better appreciation of the need for lining of canals. Judicious selection of serviceable and economical lining at the first instance and subsequently proper execution of the work while laying the canal lining reflects considerably in achieving overall economy in the project. Guidance with regard to the selection of canal lining for any particular canal is given in IS 10430 : 1982 `Criteria for design of lined canals and guidelines for selection of lining'. However, having once decided to adopt the use of polyethylene film in any particular canal, this standard would give necessary guidance for providing such lining. Considerable experience is available in the country~with regard to the use of polyethylene film as lining. The experience pooled from various organizations and extensive investigations have helped in the formulation of this standard. Tbis standard was first published in 1980. Based on further experience gained in the past 15 years-this revision has been prepared. The major modifications made are in respect of adopting HDPE as a membrane also, besides elaborating the method of lining. In view of the fact that use of HDPE and LDPE films, as membranes for lining, are both now being covered in this revision, the title of the standard has been suitably modified. For the purpose of deciding whether a particular requirement oftlris standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 `Rules for rounding off numerical values ( revised )`. The number of significant places retained inthe rounded off value should be the same as that of the specified value in this standard. IS 9698 : 1995 Indian Standard LININGOFCANALSWITHPOLYETHYLENE FILM -CODEOFPRACTICE (First Revision) 1 SCOPE This standard covers aspects of lining of canals with polyethylene film. 2 REFERENCES The Indian Standards mentioned in Annex A are necessary adjuncts to this standard. 3 TERMINOLOGY 3.0 For the purpose of this standard, the following definitions shall apply. 3.1 Beaching A protective covering of pro erly acked or built-in materials on the earthen sur Pace s P opes of irrigation canals, drainagechannels, river banks, etc, to protect them from the action of water. 3.2 Subgrade The specially prepared surface, normally of soil, on which film shall be laid. 3.3 Toe-Wall A shallow wall constructed below the bed or floor level toprovide footing for the sloped pitching on the face ofan embankment. 4 MATERIALS 4.1 The low density polyethylene film shall conform to IS 2508 : 1984 and should be of nominal thickness not less than 150 microns ( thickness to be designed based on type of subgrade and water depth ) and should be black in colour. 4.2 Hi h density polyethylene film shall conform to IS 108 B9 : 1984. 5 NECESSARY INFORMATION For necessary information to be collected before commencing work reference should be made to IS10430:1982. 6 PREPARATION OF SUBGRADE 6.1 The subgrade should be prepared according to IS 3873 : 1993 to the required cross-section to accommodate the top cover. 6.2 KANKAR or any sharp angular material shall be removed to provide reascnably smooth subgrade. Any weeds, roots and vegetation, that may damage the film, shall be removed. 6.3 For smaller canals, where the width of film available is sufficient to cover the canal section from one end to the other, no toe wall is necessary and the polyethylene film lining should be laid continuously from one end to thcother. For larger canals, a masonry toe wall of appropriate size should be constructed at two extremities of the bed With a view to providing an anchor for film laid-both on bed and sides ( see Fig. I). DESIGNED BED LEVEL .A / POLYETHYLENE FILM \ ANY RIGIO LINING POLYETHYLENE FILM \\ \ MEN1 MORTAR 1151 \ 12 mm min SAND IHICW LAYER CEMENT MO FIG 1 TYPICAL LAYOUT OFA MASONRY TOE WALL 1 IS 9698 : 1995 6.4 A trench 150 x 150 mm for canals having capacity up to 10 cumecs and minimum 250 x 250 mm for canals having capacity greater than 10 cumecs, depending upon the size of the canal, at a distance of 400 mm away from the lip and 300 mm above the FSL shall be dug all along the canal length, to hold the loose end of film laid on side slopes ( see Fig. 2 ). 6.5 If the reaches are weed infected, suitable antiweed treatment of the subgrade may be done to discourage weed growth under the film. The weedicide should be selected with utmost care specially where the canal water is used for drinking/bathing purpose and should not be harmful. After completion of the spraying of weedicides and before taking up the next activity, a period of 24 h should be allowed for penetration of chemicals into the soil. 6.6 A layer of fine sand of thickness 12 mm to 25 mm should be provided over the subgrade (on bed only ) to facilitate working conditions over the film. 6.7 In the areas where there is positive evidence of termite infestation and where canal water isnot used for drinking and bathing purposes, anti-termite treatment may be provided. 7 LAYING TECHNIQUE 7.1 The film should be laid over the prepared subgrade, below the designed level to the extent of cover thickness, in strips preferably perpendicular to water flow depending upon the width of the film, width of the bed and perimeter of the section. Longitudinal joints should be avoided. 7.2 Loose ends of the film sheet should be anchored with an allowance of 500 mm for anchoring in the toe wall. A trench as given in 6.4 should be excavated and the film anchored as shown in Fig. 2 and filled up with the excavated material where earth cover is provided. Stone or concrete coping may be provided to cover the 7.4.1 Jointing of Films There are various methods of joining adjacent lengths of film sheet to avoid leakage along the joints. The suitability of a particular method would depend upon the prevailing site conditions. 7.4.1.1 Simple overlapping The method of simple overlapping is shown in Fig. 3. The simple overlap should not be less than 300 mm for earth cover and 150 mm for hard cover. Since the simple overlap is prone to leakage, it is !east preferred, yet it may be adopted for small channels. trench to avoid rainwater from filling the trench. Toe walls should be constructed at such a level that film when laid on~the bed is retained at design depth. Adequate space should be available at the toe wall for anchoring the film. 7.3 The film should be spread loosely over the subgrade so that it attains the contours of the subgrade and compensates for thermal variation during the day. It is recommended that an extra length of 3.5 percent, over the length of film required for spreading over the bed and the side slopes including anchorage, should~be provided to take care of thermal variations during the day. film is likely to be affected by very high temperatures of about 45OC obtained in summer days, it would be advisable to avoid laying of the film under such high temperatures. In case it is necessary tocontinue the workon hotdaysaswell, workingshouldberestrictedto morning hours only. As polyethylene 7.4 Adjacent layers of film should be laid in such a manner that the width of an overlap shouldnot be less than 150 mm and the overlap should point downstream. The film sheets should be joined using the methods described in 7.4.1. ___- FULL SUPPL COMPACTED FIG 2 ILLUSTRATORYLAYOUT OF POLYETHYLENEFILM CANAL LINING 2 IS 9698 : 1995 7.4.1.2Folded overlapping Two types of folded overlaps are generally used in practice. The first type is the simple folded overlap as shown in Fig. 4. In this type of overlapping, the fold should not be less than 75 mm. In the second type, folded overlaps are embedded in a trench having a minimum width of 300 mm and depth of 150 mm as shown in Fig. 5. After overlapping, the trench should be filled with excavated material orcement concrete and coping should be provided over it. 7.4.1.3 Jointing by hot bitumen of both the sheets and these should be folded as shown in Fig. 6. Thereafter, these should be covered with brick masonry profiles (Dhamalies ) at a suitable interval, depending upon the width of the film, which should come directly over~the joint at regular intervals, in order to ensure a better joint. Usage of damaged film sheet is not recommended. However, this method has been found convenient for repairing punctures in the film at site itself. In case of big holes, pieces of sheet should be pasted from both sides 7.4.1.4 Sealing by adhesive rapes The film sheet may be joined by a coat of bitumen. Bitumen of grade 85/25 and 80/100 in the ratio of 2 : 1 may be heated at a temperature of around 100' C. Heated bitumen should be tested on a small piece of film sheet so that overheated bitumen may not damage the film. After ascertaining the appropriateness of the temperature, a thick coat of tested bitumen should be applied on a 100 mm area along the width Adjacent lengths of film maybe joined with suitable adhesive tapes as shown in Fig. 7. Hydrostatic pressure and the over-layer is sufficient to make the overlap practically water-tight. However, in areas where high temperatures exist ( 40°C - 50°C ) during summers, with passage of time , under submerged conditions, the joints may open up. Soil particles creeping into thejoint while laying , may also lead to leakage. WATER FLOW I,,, ,,,,,, p-T300 / I I,,, ,I ,,,, mm OVERL;;M I I/N, SUB GRADE FIG 3 SIMPLEOVERLAP WATER I,,, FLOW 75 mm ~oLY---l ----) r1,,1, I.,,,,rl,~r,,rl,~~~I~ FILM FIG 4 FOLDED OVERLAP _- _-__ Mf fl ----- ,, /- -WATER FLOW r-----100 ///,/,//,I~ mm! FILM -I 300 mm p---- FIG 5 FOLDEDJOINTS EMBEDDED IN A TRENCH TO FACILITATELINING FIG 6 JOINTING BY HOT BITUMEN PRESSURE TAPE FIG. 7 OVERLAPJOINT WITHPRESSUP~ TAPE 3 IS 9698 : 1995 7.4.1.5 Heat sealing The overlap joints may be heat sealed with a hot iron wasshown in Fig. 8. The temperature of the iron should be adjusted and maintained at 150°C and pressed on the joint overlap for 4 s for a 150 micron film sheet. For every 50 micron increase in the film thickness, the time should be increased by one second. To avoid the risk of film sticking to the iron a poly-tetra-fluoroethylene (PTFE) impregnated glass cloth or teflon sheet or cellophane sheet should be placed between the film and the iron. NOTE methods. Heat rlow velocities greater than 0.6 m/s. 7.8.1 Earth Cover a) Minimum thickness of cover over the film sheet should not be less than 300 mm in bed and 600 mm on the sides. b) Side slopes should be designed in accordance with the stability requirements with lining in position. Side slopes not steeper than 1.5: 1 are recommended. cl If the cover material contains KANKAR or sharp angular material, a cushion layer 75 mm thick, of sieved earth ( free from KANKAR, etc) may be provided over the film. d) To prevent `beaching effect' at the water line, KANKAR or gravel of stone aggregates of size 40 to 50 mm may be spread over the cover prior to compacting,, using light rollers or manual ramming. 7.8.2 Rigid Cover a) scaling is the most effective of all the FIG 8 HEAT SEALING OF JOINTS 7.4.1.6 In all types of joints the overlap should preferably be kept normal to the flow and should point downstream of the canal. 7.5 Film should be spread on well prepared subgrade and should be held in position at two extremities of the bed by placing excavated earth on it, while two ends of film sheet are being loosely held over the embankment. 7.6 Extra length of film sheet should be placed in a trench at embankment top and covered with earth. The embankments may be then raised to designed level. 7.7 Excavated earth should be placed over the film sheet to build up the canal section. The earth layer should be compacted by using light rollers and manual templates. It may be so arranged that earth from over-excavation of an adjacent section be used for covering the film sheet in the earlier section. Thus, by the time earth cover is provided in one section, the adjacent section is ready to receive film lining. 7.7.1 The film on the bed should be covered first. To avoid any damage to the film, a layer of earth, free from gravel or granular material, should be laid and compacted over the film. 7.7.2 The remainder of the earth cover should be spread in 150 mm layers, watered and compacted using light rollers or manual templates. 7.8 Top Cover The top cover may be an earth layer of suitable thickness ( see 7.8.1 ) or of precast concrete tiles. In-situ cement concrete, stone slab ( see IS 3873: 1993 ), or bricks (see IS 3872 : 1966). However, earth cover should not be recommended for canals having 4 In case of rigid cover, it should be so placed that the aggregates do not puncture the film. b) For a better bond between the smooth surface of film land rigid cover, a 15 mm sand cushion of fine sand may be provided over the film sheet or cement slurry may be sprayed over the film before placing in-situ cement concrete asrigid cover. 8 DO'S AND DONT'S FOR POLYETHYLENE FILM FOR CANAL LINING 8.1 Do keep the rolls in original packing prior to actual use of laying and ensure that the rolls are packed properly at the time of delivery. 8.2 Do apply uniform pressure while thermal welding (heat-sealing) the film. 8.3 Don't leave unpacked rolls exposed to the sun over prolonged periods or preferably, store them indoors. 8.4 Don't rough-handle or drag rolls, as the film may get damaged in the process. 8.5 Don't let workers walk on the film wnile the lining operation is in progress to avoid puncturing the film, in case this is unavoidable, they should walk barefooted. 8.6 Don't slide cover material like bricks, etc, on the film to avoid damage and displacement. 8.7 Don't use hooks for lifting the rolls. IS 9698 : 1995 8.8 Don't drive nails into the film for holding. 9 SAFEW AGAINST KODENTS between two layers of hard surface lining in rodent infested areas so that rgdents may not attack and damage the film from outside the channel. The film should be sandwiched ANNEXA (Clu1rse 2 ) LIST OF REFERRED INDIAN STANDARDS Title Low density polyethylene (first revision ) 3872: 1966 films IS No. Title Criteria for design of lined canals and guidelines for selection of lining ( Reaffirmed 1991 ) 10330 : 19x2 Code of practice for lining of camls with burnt clay tiles (Reaffimied 1995) Laying cement concrete/stone slab lining on ca~wls -Code of pactice (second revision ) 3873:1993 10889 : 1984 High density polyethylene ( Reaffimled 1991) films Bureau of Indian Standards BIS is a statutory institution established under the Bureau oflndian StandardsAct. 1986 to promote harmonious development of the activities of standardization, marking and quality certification of goods and attending to connected matters in the country. Copyright BIS has the copyright of all its publications. No part of the prior permission in writing of BIS. This does not standard, of necessary details, such as symbols and copyright be addressed to the Director (Publications), Review of Indian Standards these publications may be reproduced in any form without preclude the free use, in the course of implementing the sizes, type or grade designations. Enquiries relating to BIS. Amendments are issued to standards as the need arises on the basis of comments. Standards are also reviewed periodically; a standard along with amendments is reaffirmed when such review indicates that no changes are needed; if the review indicates that changes are needed, it is taken .ip for revision. Users of Indian Standards should ascertain that they are in possession of the latest amendments or edition. This Indian Standard has been developed from Dot No. RVD 13 ( 155 ) Amendments Amend No. Issued Since Publication Date of Issue Text Affected BUREAU Headquarters: OF INUlAN STANDARDS Manak Bhavan, 9Bahadur Shah Zafar Marg, New Delhi 110002 Telephones : 331 01 31, 331 13 75 Telegrams: Manaksanstha ( Common to all offices ) Telephone Regional Offices : Central : Manak Bhavan, 9 Bahadur NEW DELHI 110002 Shah Zafar Marg I 3310131 3311375 37 84 99, 37 85 61 37 86 26, 37 86 62 1 60 38 20 43 25 Eastern : l/l4 C. I. T. Scheme VII M, V. I. P. Road, Maniktola CALCUTTA 700054 Northern : SC0 335-336, Sector 34-A, CHANDIGARH 160022 Southern : C. I. 7'. Campus, IV Cross Road, MADRAS 600113 (East) 23502 16,2350442 235 15 19,235' 23 15 I 632 78 92 ?l, 95 632 632 78 58 92 Western : Manakalaya, E9 MIDC, Marol, Andheri BOMBAY 400093 BHUBANESHWAR. BHOPAL. BANGALORE. Branches : AHMADABAD. HYDERABAD. GUWAHATI. GHAZIABAD. FARIDABAD. COIMBATORE. PATNA. THIRUVANANTHAPURAM. LUCKNOW. KANPUR. JAIPUR. 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